The long-term goal of this research is to understand the molecular mechanisms of drusen formation and Bruch's membrane thickening in age-related macular degeneration (AMD). The unifying hypothesis is that protein modifications are causally involved in both processes. Drusen are extracellular deposits that form between the retinal pigment epithelium and Bruch's membrane and confluent drusen are the hallmark risk factor for developing AMD. The progression of AMO might be slowed or halted if drusen and Bruch's membrane changes can be modulated. The proposed research will identify proteins and lipids in drusen and Bruch's membrane from healthy and AMD donor tissues and characterize associated protein modifications and reactive lipid fragments. Four specific aims will test the following hypotheses: (i) that the drusen proteome differs among drusen sub-types; (ii) that the Bruch's membrane proteome varies with age and state of health; (iii) that lipid oxidation products in drusen and Bruch's membrane vary with age and state of health; (iv) that oxidative protein modifications contribute to drusen formation and Bruch's membrane thickening. Mass spectrometric methods will be used to identify and characterize proteins, phospholipids and lipid oxidation products. Immunocytochemistry will be used to confirm protein localization to drusen and Bruch's membrane. Western analyses, electrophoretic mobility shifts and bioinformatic tools will be used to detect protein modifications. The results will help establish a firm link between oxidative damage and the pathogenesis of AMD and provide new opportunities for developing strategies and therapies for preventing or limiting the complications of AMD.